Road basket and method of making same

ABSTRACT

An improved road basket including a non-metallic dowel, a first support frame including a first support frame first leg and a first support frame first cup moldably secured to the dowel first end, and a second support frame including a second support frame first leg and a second support frame first cup moldably secured to the dowel second end. Multiple dowels can be secured in similar fashion to additional leg members. Preferably, the first support frame first leg and a first support frame second leg are connected by a base frame member. In addition, the first support frame first leg and the first support frame second leg may be connected by an intermediate frame member. The frame may be constructed of a single piece. The dowel is preferably made from fiberglass or glass fiber reinforced polymer and the frame is preferably high density polyethylene.

BACKGROUND OF THE INVENTION

This invention relates to a composite dowel basket for use generally in jointed plane concrete pavement applications and a method for making the same. More specifically, though not exclusively, the present invention relates to a composite dowel basket in which the dowels themselves are secured in place during the molding process such that no on-site assembly is required. The assembly is easy to use, lightweight and non-corrosive.

Currently, reinforced concrete employs a system of dowels which is supported by a wire support structure to elevate the dowels to a desired height within the poured concrete structure. For example, when roads are poured, a system of dowels and wire support structures work together to form what is typically known as a basket that allows the concrete to be poured over the dowels and its support structure. As discussed in U.S. Pat. No. 6,092,960, which is incorporated herein by reference, it is well-known that concrete has a high compressive strength with low tensile and shear strengths and that concrete expands and contracts due to changes in temperature. Previously, dowel bars have been incorporated into concrete structures to transfer shear loads at joints and allow the concrete blocks or slabs to expand in a desired direction. By controlling the direction of expansion of the slabs, engineers can minimize the likelihood that highways and other surfaces will become uneven.

As others have noted, steel dowels are typically used in current construction methods as it was considered a cost effective way to provide the necessary strength required by the application. Unfortunately, the steel in dowels has a tendency to corrode after years of use and this corrosion negates its beneficial incorporation.

To solve this problem, others have suggested using composite materials such as fiberglass dowel bars and fiber composite dowels to replace the steel dowel bars. While composite or fiberglass materials have been used to replace the steel dowels in the prior art, such incorporation also presents problems. For example, these fiberglass or composite materials can no longer be welded to their support structure. Thus, the prior art has developed numerous examples of securing apparatuses. For example, U.S. Pat. No. 6,092,960 to McCallion, describes a series of clips 30, 40 that may be used to secure the composite or fiberglass dowel to its underlying steel support structure. This requires extensive labor to assemble all of the components and ensure that the clips remain attached. Because the clips are not permanently secured, they may also cause problems during installation and pouring of concrete if things fall apart.

Others have attempted to support the existing rebar using plastic molded components. For example, U.S. Pat. No. 5,555,693 to Sorkin discloses a chair for use in construction that includes an indentation suitable for the receipt of rebar. A similar support structure is described in U.S. Patent Application Publication No. 2004/0261352 to Bennett et al. These structures are designed to hold rebar in place during pouring. Unfortunately, as these structures are separate from the rebar itself, they are prone to failure during the pouring process as they can easily be tipped over or separated from the rebar. To secure them to the rebar requires additional labor or materials. Also, these devices are designed for rebar, not the necessary dowels for joint load transfer.

It is therefore desirable to provide an improved road basket that requires no on-site assembly, uses no corrosive dowel or wire material and attempts to address some of the issues with the prior art.

FEATURES OF THE INVENTION

A general feature of the present invention is an improved road basket and method of making same which addresses some of the issues with the prior art.

A further feature of the present invention is the provision of an improved road basket and method of making same which avoids the use of corrosive materials.

Another feature of the present invention is the provision of an improved road basket and method of making same which is easy to manufacture.

Still another feature of the present invention is the provision of an improved road basket and method of making same which is easy to install.

Another feature of the present invention is the provision of an improved road basket and method of making same which requires no on-site assembly.

Another feature of the present invention is the provision of an improved road basket and method of making same which is low cost to manufacture.

Still another feature of the present invention is the provision of an improved road basket and method of making same which is lightweight.

SUMMARY OF THE INVENTION

The present invention generally comprises an improved road basket including a non-metallic dowel having a dowel first end, a dowel second end, and a dowel intermediate portion, a first support frame including a first support frame first leg and a first support frame first cup moldably secured to the dowel first end, and a second support frame including a second support frame first leg and a second support frame first cup moldably secured to the dowel second end. Multiple dowels can be secured in similar fashion to additional leg members of the frame. Preferably, the first support frame first leg and a first support frame second leg are connected by a base frame member. In addition, the first support frame first leg and the first support frame second leg may be connected by an intermediate frame member. The first support frame and the second support frame may be constructed of a single piece. The dowel is preferably made from fiberglass or glass fiber reinforced polymer and the frame is preferably high density polyethylene.

During manufacturing, the dowels are protruded, depending on their construction, and cut to a desired length. Once cut to a desired length, at least a portion of each dowel is placed in an injection mold. The mold is then closed around at least a portion of the dowel and the frame is formed by injecting material into the mold. At least a portion of the frame is overmolded around the portion of the non-metallic dowel in the mold. Preferably, many dowels may be placed in the mold simultaneously and the frame members may be formed simultaneously such that when the frame and dowel structure is removed from the mold, the road basket is formed.

Preferably, the frame members are made from injection of a high density polyethylene or HDPE structural foam into the mold. During the cutting process, slight deformations of the dowel may occur. These deformations serve to reinforce the hold of the frame members on the dowel during the over-molding process.

Once formed, the complete road basket is transported to a work site. At the work site, the users may cut the road basket to a desired length using readily available cutting tools, including saws generally used to cut wood. If necessary, the road basket may be secured in a desired location on the work site by securing an anchor to the first support frame. These anchors may be U-shaped or any other shape of anchor which is capable of holding the road basket in place.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of the improved road basket of the present invention.

FIG. 2 is a close-up view of one dowel frame connection point of the present invention.

FIG. 3 is a cross-sectional view of an embodiment of the present invention.

FIG. 4 is a perspective view of a preferred embodiment of the frame of the present invention.

FIG. 5 is a perspective view of a preferred embodiment of the present invention.

FIG. 6 is a perspective view of a section of the preferred embodiment of the present invention.

FIG. 7 is a front view of a section of the preferred embodiment of the present invention.

FIG. 8 is a front view of the preferred embodiment of the present invention.

FIG. 9 is a side view of the preferred embodiment of the present invention.

FIG. 10 is a top view of the preferred embodiment of the present invention.

FIG. 11 is a cross-sectional view of the preferred embodiment of the present invention.

FIG. 12 is a cross-sectional side view of the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described as it applies to its preferred embodiment. It is not intended that the present invention be limited to the described embodiment. It is intended that the invention cover all modifications and alternatives, which may be included within the spirit and scope of the invention.

Referring to the drawings, FIG. 1 illustrates the preferred embodiment of the improved road basket 10 of the present invention. Preferably, the road basket 10 includes a plurality of non-metallic dowels 12. The dowels may be made from any desired non-corrosive material. Preferably, the dowels 12 are made from fiberglass or a glass fiber reinforced polymer. The non-metallic dowels 12 are generally held in an elevated position by a frame 14.

As shown in FIGS. 1-12, the frame 14 secures multiple dowels parallel to each other and parallel to the ground simplifying installation of the dowels in a slip form paving process. Preferably, the frame 14 is manufactured using an injection molding process. The frame 14 is also preferably made from a non-corrosive material and preferably made from high density polyethylene structural foam. The combination of these selected materials, glass fiber reinforced polymers and high density polyethylene (HDPE) structural foam, provides a road basket 10 which is lightweight and easy to handle. It also allows the road basket 10 to be cut using a variety of tools, including readily available wood cutting saws.

A close-up of the connection point between the dowel 12 and the frame 14 is shown in FIG. 2. As shown in FIG. 3, the dowel 12 includes a dowel first end 16, a dowel second end 18 and an intermediate portion 20. A first support frame 22 and a second support frame 24 are also shown. The first support frame 22 generally includes a first support frame leg 26 and a first support frame cup 28. Similarly, the second support frame 24 includes a second support frame leg 30 and a second support frame cup 32. During the manufacturing process, the first support frame cup 28 is overmolded around the dowel first end 16. Similarly, during the manufacturing process, the second support frame cup 32 is preferably overmolded around the dowel second end 18. In this manner, the dowel 12 is secured to the frame 14 without any glue or welding required. This saves considerably on time and labor costs.

As shown in FIG. 4, the frame 14 may include multiple frame legs and cups. For example, the first support frame leg 26 and first support frame cup 28 are shown in FIG. 4 next to a first support frame second leg 42 and first support frame second cup 44. The first support frame second cup 44 is secured to a second dowel 34 having a second dowel first end 36, a second dowel second end 38 and a second dowel intermediate portion 40 as shown in FIG. 1. The first support frame second cup 44 is secured to the second dowel first end 36 as discussed above relative to the first support frame cup 28 and the first dowel first end 16. This process can be repeated to include as many dowels as desired. As also shown in FIG. 4, the frame 14 may include a base frame member 46 and an intermediate frame member 48. The base frame member 46 provides a bottom surface for the frame 14 stabilizing the road basket 10 on the ground or installation surface.

During manufacturing, the dowels 12 are extruded or protruded, depending on their construction, and cut to a desired length. Preferably, an FRP pultrusion machine from Marine Products, Inc. or Liberty Pultrusions is used. Once cut to a desired length, at least a portion of each dowel 12 is placed in a structural foam injection molding machine, such as one from Uniloy Milacron using a mold, such as one from 20/20 Custom Molded Plastics. The mold is then closed around at least a portion of the dowel 12, such as the dowel first end 16. After the dowel 12 sections 16, 18 have been placed in the mold, the mold is closed and the injection process begins. Initially, the injected material, preferably the HDPE structural foam, will be heated to a first formation temperature as needed to ensure the foam is generally in a liquid or flowing state. The heat and pressure from the HDPE structural foam will create a thermoset bond between the frame 14 and the dowel 12 as the HDPE structural foam cools to a second formation temperature in which the HDPE structural foam is generally in a solid state. The melting temperature or first formation temperature will vary by material and is typically specified by the material manufacturer.

When the overmolding occurs over a portion of the dowel 12, a bond is formed at the interface between the outer surface of the dowel 12 and the inner surface of the cup 28 as the cup 28 and interface are formed simultaneously. This bond at the interface can be broken by the forces of the expansion and contraction of the concrete, which is the design intent, which corresponds to current practice of welding every other end of steel dowel to wire frame. In this manner, the non-metallic road basket 10 of the present invention maintains the desired qualities of the prior steel dowels while providing additional benefits of non-corrosion and easy installation and manufacturing.

During the molding process, the frame 14 is formed by injecting material into the mold. For example, as shown in FIG. 1, the first support frame 22 is formed by the injection molding process. Material, such as the high density polyethylene structural foam is injected into the mold, as is well known in the art. The first support frame leg 26 is formed and the material then flows around the dowel first end 16 to form the first support frame cup 28. Thus, at least a portion of the frame is overmolded around the portion of the non-metallic dowel in the mold. Preferably, many dowels may be placed in the mold simultaneously and the frame members may be formed simultaneously such that when the frame and dowel structure is removed from the mold, the road basket 10 is formed.

Once formed, the complete road basket 10 is transported to a work site. At the work site, the users may cut the road basket 10 to a desired length using readily available cutting tools, including saws generally used to cut wood. If necessary, the road basket 10 may be secured in a desired location on the work site by securing an anchor to the first support frame. These anchors may be U-shaped or any other shape of anchor which is capable of holding the road basket in place.

A general description of the present invention as well as a preferred embodiment of the present invention has been set forth above. Those skilled in the art to which the present invention pertains will recognize and be able to practice additional variations in the methods, systems and apparatuses described which fall within the teachings of this invention. Accordingly, all such modifications and additions are deemed to be within the scope of the invention which is to be limited only by the claimed appended hereto. 

1. An improved road basket, the road basket comprising: a non-metallic dowel having a dowel first end, a dowel second end and a dowel intermediate portion; a first support frame including a first support frame first leg and a first support frame first cup moldably secured to the dowel first end; and a second support frame including a second support frame first leg and a second support frame first cup moldably secured to the dowel second end.
 2. The road basket of claim 1 further comprising a second non-metallic dowel having a second dowel first end, a second dowel second end and a second dowel intermediate portion, a first support frame second leg and a first support frame second cup moldably secured to the second dowel first end.
 3. The road basket of claim 2 wherein the first support frame first leg and first support frame second leg are connected by a base frame member.
 4. The road basket of claim 2 wherein the first support frame first leg and the first support frame second leg are connected by an intermediate frame member.
 5. The road basket of claim 1 wherein the first support frame and the second support frame are a single piece frame.
 6. The road basket of claim 5 wherein the single piece frame encloses the dowel first end, dowel second end and dowel intermediate portion.
 7. The road basket of claim 1 wherein the dowel is comprised of fiberglass.
 8. The road basket of claim 1 wherein the dowel is comprised of glass fiber reinforced polymer.
 9. The road basket of claim 1 wherein the first support frame is comprised of high density polyethylene.
 10. A method of manufacturing an improved road basket, the method comprising: pultruding a non-metallic dowel; cutting the non-metallic dowel to a desired length; placing at least a portion of the non-metallic dowel in an injection mold; closing the mold around the portion of the non-metallic dowel; and forming the road basket by molding a frame, with at least a portion of the frame overmolded around the portion of the non-metallic dowel in the mold.
 11. The method of claim 10 wherein the non-metallic dowel includes a first end and a second end; the mold is closed around the first end and a first frame is formed with at least a portion of the first frame overmolded around the first end.
 12. The method of claim 11 wherein the mold is closed around the second end and a second frame is formed with at least a portion of the second frame overmolded around the second end.
 13. The method of claim 10 wherein the non-metallic dowel is comprised of fiberglass.
 14. The method of claim 10 wherein the non-metallic dowels is comprised of glass fiber reinforced polymer.
 15. The method of claim 10 wherein the frame is comprised of high density polyethylene.
 16. The method of claim 16 wherein the deformation is secured within the overmold portion of the frame.
 17. A method of using an improved road basket, the method comprising: cutting a road basket to a desired length, the road basket comprising a non-metallic dowel having a dowel first end, a dowel second end and a dowel intermediate portion, a first support frame including a first support frame first leg and a first support frame first cup moldably secured to the dowel first end, and a second support frame including a second support frame first leg and a second support frame first cup moldably secured to the dowel second end; and securing the road basket in a desired location by securing an anchor to the first support frame.
 18. The method of using an improved road basket of claim 17, the method further including forming an interface, wherein the interface has a first formation temperature for forming around an outer surface of the dowel first end and a second formation temperature for securing the dowel first end to the first support frame first cup.
 19. An improved road basket, the road basket comprising: a dowel wherein the dowel includes an outer surface; a frame connected to the dowel, the frame including a cup wherein the cup includes an inner surface; and an interface between the outer surface of the dowel and the inner surface of the cup and wherein the dowel and the cup are secured together at the interface.
 20. The improved road basket of claim 19 wherein the interface has a first formation temperature for forming around the outer surface of the dowel and a second formation temperature for securing the dowel to the cup. 